Okay let's look at precedent shall we? Would Scalia's decision in Cruzan suffice? Who did he say should make this decision? If you are a South Carolinian, get to it and save this man's life. Allow your legislature to act as they see fit. Call officials you elected.
I realize some around here would federalize every moral decision under the sun if Republicans remain in charge, however Madison was quite clear. I also realize Republicans selectively forget the Framers when it stands in the way of their 'crusades', however conservatives don't.
What decision? Are you referring to who gets to decide to kill another person? Should the spouse decide whether or not to kill them? Should a municipal judge decide whether or not to kill them? Should the Congress decide whether or not to kill them?
You ask the question as though somebody MUST decide, and it's just a matter of who should decide.
Is this a decision that must only be made about disabled people, or are others in need of this decision as well? Who should decide whether or not to kill my Jewish neighbor? Who should decide whether or not to kill my Mexican neighbor? Who should decide whether or not to kill my Baptist neighbor?
Or maybe you would prefer to base it on an individual's circumstances that affect the quality of their lives. Who should decide whether or not to kill a recently widowed man? Who should decide whether or not to kill a woman whose baby just died? Who should decide whether or not to kill a homeless man? Obviously all those people are suffering. Killing them would no doubt end their suffering.
Are those all private family matters? Should we accept that as long as they're able to speak on a certain level, they can make that decision themselves, but if not, the next of kin should decide? At what level should a person be required to speak in order to get to decide whether or not they should be killed? College level? High school level? And do they have to speak English, or will just any language suffice?
Or maybe we shouldn't single out any particular group of people. Maybe every individual should be subject to this decision. We can eliminate the taboo in killing, as long everybody follows the rules. Each of us will have a Designated Decision Maker (DDM) to decide our fate. The DDM will get to choose the hour and manner of our deaths. If you want to kill somebody for whom you are not the DDM, you'll need to petition the DDM for permission, and pay whatever surcharge the DDM deems appropriate. Parents will automatically be the DDM for their children. Upon marriage, the title of DDM automatically transfers to the spouse. Every one of us will have one person somewhere who gets to decide the time and method of our death. You've already established that the person for whom the decision is being made should have no say in the matter. (Or does your opinion on that only apply to Terri Schiavo Schindler, Scott Thomas, and Jimmy Chambers?) So, resisting your DDM's attempts to kill you will be a crime, punishable by a more turturous death than originally intended.
Or do you reserve this sacred practice of "deciding" solely for disabled people's decision makers?